Telephonic system



(No Model.) i

J. P. BARRETT.

TELEPHONIG SYSTEM. No. 284,594. Patented Sept. 11, 1888.

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' provided with a spring, c, which is just strong yenough to overcome the normal attraction oi' UNITED STATES PATENT OFFICE.

JOHN P. BARRETT, OF CHICAGO,l ILLINOIS.

, TELEPHONIC SYSTEIVI.y

SPECIFICATION forming part of Letters Patent No. 284,594, dated September 11, 18.83.

Application tiled October 9, 1862. (No model.)

T0 all whom it may concern:

Be it known that I, JOHN P. BARRETT, a citizen of the'United States of America, re siding at Chicago, in the county of Cook and State of Illinois, have invented an Improvement in Telephonie Systems, of which the following is a/s'peciicati-on. l

My @ventanillas/fdiits objects to facilitate the transmission of calland answer signals between outlying sta-tions and a central telephone-oiiice, and to enable stations of a telephonie system to be placed in and out of telephonie communication quickly and by means of simple apparatus.

lVith these objects in view the invention consists in certain novel combinations and arrangements of a main, local, and branch circuits, switching devices, and telephonie com-1 municating apparatus, which will be hereinafter fully described, and4 pointed out in the; appended claims. Q In order to enable others skilled in the artv to which myinvcntion appertains to make and: use the same, I will now proceed to describe, its construction and operation, referring` to the'y accompanying drawing, which shows 'a tele-I phone system such as I describe.`

A represents the main battery, located at the central office, and in a metallic circuit or? main line marked B, in which I have indi-.Y cated two stations, O O, and shown a third in detail at O. Each station O O is provided with a box, D, containing` an alarm mechanism, d, provided with an operatii'ig-lever, d, and a spring actuated hammer, c, pivoted within the box: and adapted to Strike an alarm upon a bell, b. b is an electro-magnet within thebox D, andconnected to the main line, as shown, and also to the alarm mechanism,`by a wire, b2. This; magnet is furnished with a hinged armaturetrigger, c, which engages with the hammer a, when it is drawn back, and prevents its contact with the bell. The armature c is also the electro-magnet b and keep them from contact.

c represents a wire connecting the main line within the-box D with a post, ai, with which the hammer c contacts when at rest, as will be presently understood.

vThe box D is connected by a wire, e, and:

switchlever e to the main line on one side l/with the branch circuit by arspringjz, and

and directly to the main line on ythe other. This switch-lever c is electrically connected at one end with the mainline, and at the other end with a local circuit, B', containing a local battery, B2, a transmitter, E, and the primary of an induction-coil, f, and connecting with the switch'at its pivotal point. In connection with this primary coil f, I use a secondary coil, f', connected by wire D2, containing a receiver, E, with the main line, whereby 'a current over the local circuit B will induce one through the secondary coil and receiver andof to the main line, as will be readily understood.

Vhen not in use, the receiver Ehangs upon a bracket, g, under the outer end of the switchlever e, and while making the connection between the switch and the main line attached to said bracket the other end of the switchlever is thrown down and breaks the connection of the local circuit, the receiver being short-circuited. Vhen, however, the receiver vis taken down vfor use, the connection between the switch-lever and bracket is broken, and the spring el throws up the other end of the switch and makes the electrical connection of the local circuit, and places the receiver directly in the mainline.

At the central office the line connects with apivoted key, F, which is by a spring, g', held in position to contact with the wire g? at one end, as shown. This wire connects with a switch-leven?, connecting with a bracket, g3,

exactly, as already described, for the station Y C', and thence the line passes on through arelay,`G, to the main battery A. The switchlever c3 is provided with a spring, 6*, and makes electrical connection at one end with the main line, and at the other end with a local circuit, B3, containing a local battery, B4, a transmitter, E2, and the primary of an induction-coil, f2, and connecting with the switch at its pivotal point. In connection with the primary coil f 2 there is a secondary one, f3, connected by wire D3, containinga receiver, E3, with the main line, whereby a current over the local circuit B3 will induce one through the secondary coil and receiver and off to the main line, as before described.

Above the key F connection is made to the main line by a local circuit, H, passing through the armature h of the relay G, lwhich is held from contact with the relay and into contact IOO thence passes through a local battery, H', then Y register is also broken, and when the main line is closed at the key the magnet will attract the armature h ,and the register be operated, as this armature is attracted or released rby the impulses of the main current. The other end of the key, when depressed, contacts with a wire, 73, passing to a battery, I, connected to the main battery A.

W'hen the line is in its normal state,the cur-` rent from the battery A passes over the line throughthe relay G, bracket y?, switch e3, wire g2, `key F, and line B, through the stationboxes, and back to the main battery through a galvanometer, I. When the central oice is to be called from a station, the hand-lever patented to s. D. Field, No. 189,717, A131117,

The action of pulling down the lever d throws back the hammer a through suitable connecting mechanism, (not shown,) and engages it withV the armaturelever c, the current from the main line passing through the mechanism d, wire b2, and magnet b. The operator at the main office immediately depresses the key F, breaking the connection first of the register-circuit H and then with the wire g2,

` connecting to the relay, and making the connection with the wire 7L, thereby throwing into the line the auxiliary battery I, the strength of which, added to that of the main battery A, so intensifies the' magnet b at the station that the resistance of spring c is overcome and the armature-trigger c drawn back, which releases the spring-hammer a to strike a blow upon the bell b and notify the operator that his call is received. The register being operated by the making and breaking of the local circuit at the relay, it is necessary to break this circuit at the key during the sending of an answer-signal, in order that the register may not be operated uselessly. The armature of the relay is always normally attracted and held, and thus breaks the register-circuit;. but when the break in the main current through the relay-magnet occurs, the armature springs oil' and makes connection in the register-circuit to record the call or message. The keyF is made solid, with a spring upon its end, so bent asto still make the outer connection after the inner one is broken, thus enabling one to break before the other. The

operator at the 'station then takes down the receiver, thereby throwing his branch circuitv `into the main line, and the operator at the -central oiice having done the same4 and'allowed the key F toresume its normal position, the message is sent and received in the usual manner. As soon as the key F is released, the battery I is again c ut out, the intensity of the magnet b is lowered, the spring throws the armature on', and the current resumes its normal course over the wire b2, spring c', armature c, hammer a, post a2, and wire a to the main line.

It will be observed that when the key F is depressed, the connection is broken first with the circuit in which the register is situated and then with the local branch of the main ofiice.. This is to prevent the running o' and wasting of the strip of paper on the register, which would occur if the breaking of the connection should be reversed.

Having thus fully described my invention, what I claim as new, fand desire to secure by Letters Patent, is-

1. In atelephone-station apparatus, the combination, with a vnormally-closed main line, a y local circuit including the primary of the induction-coil of a transmitter arranged for connection with the main line, Aand a constantly-closed branch circuit including a rei ceiver, of a switch-lever, and contacts adapted to be operated by the hanging of the receiver upon its support to break the local circuit, short-circuit the receiver, and shunt the main `circuit around it, and to be operated by the l cuit and include the receiver in the main circuit directly, substantially as described.

2. In the central-ofice apparatus of a telephone system, the combination, with the main battery andy normally-'closed main line, an auxiliary battery normally out of circuit, and a local circuit, of the key and connections ar ranged to simultaneously add the auxiliary 1 battery to line and break `the local circuit, substantially as described.

3. In the central-office apparatus of a telephone system, the combination, with the main `line and branch circuit including the relay, the local circuit including the register and a local battery, the armature of said relay arranged to make and break said local circuit, 4 and the branch wire connected with one pole `of a battery, the other pole of which is connected with the main line leading outward in one direction, of the key arranged to, by a single movement, connect said battery and branch wire with the main line leading in the other direction, to break the local registercircuit, and after a slight interval to break the branch circuit including the relay,'substan tially as described, and for the purpose set forth.

' In testimony whereof I aX my signature in presence of two witnesses.

JOHN I. BARRETT. Witnesses: W. C. MCARTHUR,

J. E. SrEvENsoN.

removal of the receiver to close the local cir# IIO 

